Observation device
The observation apparatus addresses the challenge of varying illumination angles by using multiple concentrically arranged illumination units to switch between angles, capturing and combining images for optimal contrast and visibility across complex samples.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- EVIDENT CORP
- Filing Date
- 2021-11-22
- Publication Date
- 2026-06-24
Smart Images
Figure 0007879680000001 
Figure 0007879680000002 
Figure 0007879680000003
Abstract
Description
Technical Field
[0001] The disclosure of this specification relates to an observation device.
Background Art
[0002] As observation methods used in microscopes, oblique observation and dark field observation, in which illumination light is irradiated on a sample from a direction inclined with respect to the optical axis, are known. Techniques related to these observation methods are described in, for example, Patent Document 1 and Patent Document 2.
[0003] Patent Document 1 describes an observation device that observes a sample illuminated by a ring illumination unit in which a plurality of light emitting elements are arranged in a ring shape through an aperture having an opening at a position eccentric with respect to the optical axis. In the observation device described in Patent Document 1, the illumination direction and the observation direction can be adjusted independently.
[0004] Patent Document 2 describes an enlarged observation device having a light projecting unit that irradiates an observation object with lights having different emission directions. In the enlarged observation device described in Patent Document 2, a plurality of image data indicating images of the observation object when lights in a plurality of emission directions are respectively irradiated on the observation object can be generated.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0006] Incidentally, in the oblique and dark-field observations mentioned above, illuminating the sample with illumination light from a direction inclined with respect to the optical axis can enhance the contrast of samples that are difficult to image well under normal illumination conditions. However, the optimal illumination angle varies depending on the sample, and may even differ from place to place within the same sample.
[0007] For example, in the case of a sample with deep grooves, if the illumination angle is too large, the illumination light will not reach the bottom surface of the grooves, making it impossible to visualize the bottom surface properly. On the other hand, if the illumination angle is too small, the overall contrast of the sample will decrease, and an image with a sense of depth will not be obtained.
[0008] Based on the circumstances described above, one aspect of the present invention is to provide a technology that enables good observation of various samples. [Means for solving the problem]
[0009] An observation apparatus according to one aspect of the present invention comprises an imaging unit for imaging a sample, an observation optical system for projecting an optical image of the sample onto the imaging unit, and a plurality of illumination units that irradiate the sample with illumination light at different angles relative to the optical axis of the observation optical system, each having a different angle of incidence to the sample, and are arranged concentrically around the optical axis and at the same height. By switching the illuminated section, it is possible to sequentially switch between a first illumination state in which the sample is irradiated at a first incident angle and a second illumination state in which the sample is irradiated at a second incident angle. Multiple lighting units, The aforementioned The control unit sequentially switches the illuminated illumination unit from among multiple illumination units to multiple different illumination states to acquire multiple images of the sample captured by the imaging unit. The control unit acquires the plurality of images by obtaining at least an image of the sample taken under the first illumination state and an image of the sample taken under the second illumination state. It is equipped with the following. The control unit generates a new image of the sample based on the plurality of images obtained by sequentially switching between the plurality of illumination states. [Effects of the Invention]
[0010] According to the above embodiment, various samples can be observed well. [Brief explanation of the drawing]
[0011] [Figure 1] This diagram illustrates the configuration of the observation device 10. [Figure 2] This diagram illustrates the configuration of the lighting device 24. [Figure 3] It is a diagram for explaining the difference in the irradiation angle of illumination light. [Figure 4] It is a diagram illustrating the shape of the sample S. [Figure 5] It is a flowchart showing an example of the processing performed by the observation device 10. [Figure 6] It is a diagram for explaining the composite image. [Figure 7] It is a diagram illustrating the configuration of the illumination device 28. [Figure 8] It is a diagram illustrating the configuration of the illumination device 29. [Figure 9] It is a flowchart of the processing according to the first embodiment performed by the observation device 10. [Figure 10] It is an example of an application screen. [Figure 11] It is a diagram for explaining the pre-scan. [Figure 12] It is a diagram for explaining the height calculation. [Figure 13] It is a diagram for explaining the image acquisition for the composite image. [Figure 14] It is a diagram for explaining an example of an image synthesis method. [Figure 15] It is a diagram for explaining another example of an image synthesis method. [Figure 16] It is a diagram for explaining the image acquisition in the pitch feed mode. [Figure 17] It is a flowchart of the processing according to the second embodiment performed by the observation device 10. [Figure 18] It is another example of an application screen. [Figure 19] It is a flowchart of the processing according to the third embodiment performed by the observation device 10. [Figure 20] It is a flowchart of the processing according to the fourth embodiment performed by the observation device 10. [Figure 21] It is yet another example of an application screen. [Figure 22]This diagram illustrates the hardware configuration of the computer 100 for implementing the control device 30. [Modes for carrying out the invention]
[0012] Figure 1 is a diagram illustrating the configuration of the observation device 10. The observation device 10 comprises a microscope 20, a control device 30 for controlling the microscope 20, a display device 40, and an input device 50.
[0013] The microscope 20 includes an optical head 21, a light source 22, an observation optical system 23, an illumination device 24, a stage 25, a frame 26, and a digital camera 27. The light source 22 and the digital camera 27 are provided in the optical head 21 along with optical path splitting elements (splitters) such as half mirrors, dichroic mirrors, and polarizing beam splitters. The light source 22 is positioned on one of the optical paths branched by the splitter, and the digital camera 27 is positioned on the other.
[0014] The optical head 21 is held in the frame 26. The optical head 21 is an example of a focusing unit that changes the distance between the sample S and the observation optical system 23, and is movable in the Z direction parallel to the optical axis of the objective lens 231 while being held in the frame 26. The movement of the optical head 21 in the Z direction is controlled by the control device 30. The control device 30 controls the movement of the optical head 21 while detecting its position in the Z direction by, for example, reading the position information of a linear scale fixed to the frame 26 with a scale head fixed to the optical head 21.
[0015] Light source 22 is a light source for incident illumination, and is, for example, a white LED. It may also be a xenon lamp, a halogen lamp, or the like. The illumination light emitted from light source 22 is collimated by an illumination lens. The collimated illumination light is reflected by a splitter and irradiated onto the sample S placed on the stage 25 via the objective lens 231.
[0016] The observation optical system 23 projects an optical image of the sample S illuminated by illumination light onto a digital camera 27. The observation optical system 23 includes, for example, an objective lens 231 and an imaging lens. The objective lens 231 is switchable via a revolving nosepiece. Multiple objective lenses of different magnifications may be mounted on the revolving nosepiece, and any objective lens from among the multiple objective lenses may be placed in the optical path according to the user's selection.
[0017] The digital camera 27 is an example of an imaging unit that images a sample. The digital camera 27 includes an image sensor. The image sensor is, for example, a CMOS image sensor, but it may also be a CCD image sensor. The digital camera 27 images the sample and outputs the image of the sample to the control device 30. Hereafter, in order to distinguish it from the composite image described later, the image generated by the digital camera 27 will be referred to as the captured image as needed.
[0018] The stage 25 on which the sample S is placed includes an XY stage 25a and a Z stage 25b. The XY stage 25a is, for example, an electric stage, and its position in the XY direction perpendicular to the optical axis of the objective lens 231 is controlled by a control device 30. The XY stage 25a is mounted on the Z stage 25b.
[0019] The Z-stage 25b is an example of a focusing unit that changes the distance between the sample S and the observation optical system 23. The Z-stage 25b is, for example, a manual stage, and its position in the Z direction can be adjusted with a handle (not shown). Note that the XY stage 25a and Z-stage 25b are not limited to this example and may be motorized or manual stages, respectively.
[0020] The illumination device 24 is a ring illumination device that irradiates the sample with illumination light at a larger angle of incidence than the incident illumination performed via the objective lens 231. The illumination device 24 is arranged, for example, to surround the outside of the lens barrel of the objective lens 231. Details of the configuration of the illumination device 24 will be described later.
[0021] The control device 30 is a device that controls the microscope 20 and is an example of a control unit of the observation device 10. The control device 30 may be composed of multiple devices. For example, the control device 30 may include a microscope controller that is mainly responsible for controlling the operation of the motorized part of the microscope 20 and a general-purpose computer that is mainly responsible for image processing of images acquired by the microscope 20.
[0022] The display device 40 is an example of a display unit of the observation device 10. For example, it is any display, including a liquid crystal display or an organic EL display. The input device 50 is any input device such as a keyboard, mouse, touchpad, or joystick. Alternatively, the input device 50 may be a handle or switch for operating the stage 25 or the optical head 21.
[0023] In the observation device 10, the microscope 20 can perform reflected illumination using the light source 22 and ring illumination using the illumination device 24 under the control of the control device 30. The control device 30 may cause the microscope 20 to perform only one of reflected illumination or ring illumination during observation and display the image acquired using the microscope 20 on the display device 40. Alternatively, the control device 30 may cause the microscope 20 to perform both reflected illumination and ring illumination simultaneously during observation and display the image acquired using the microscope 20 on the display device 40. In other words, the observation device 10 may perform bright-field observation using reflected illumination, dark-field observation using ring illumination, or so-called mixed observation using reflected illumination and ring illumination.
[0024] Figure 2 is an example diagram illustrating the configuration of the lighting device 24. Figure 3 is a diagram illustrating the difference in the irradiation angle of the illumination light. The configuration of the lighting device 24 will be described below with reference to Figures 2 and 3.
[0025] The illumination device 24 includes a plurality of illumination units (illumination unit 241, illumination unit 242, illumination unit 243) that irradiate the sample S with illumination light at different angles relative to the optical axis of the objective lens 231 (observation optical system 23).
[0026] As shown in Figures 2 and 3, the multiple illumination units are positioned at different distances from the optical axis to irradiate the sample S with illumination light at different angles. More specifically, the multiple illumination units are arranged at the same height in a concentric circle around the optical axis of the objective lens 231 (observation optical system 23). The multiple illumination units are arranged in the order of illumination unit 243, illumination unit 242, and illumination unit 241, from the one closest to the optical axis, and each irradiates the sample S with illumination light at incident angles θ3, θ2, and θ1 (θ3 < θ2 < θ1), respectively.
[0027] Each of the multiple lighting units has an annular shape and contains multiple light-emitting elements 240 arranged in a ring shape around the optical axis. More specifically, each of the multiple light-emitting elements 240 is arranged at regular intervals in the circumferential direction around the optical axis. The light-emitting elements are, for example, white LEDs.
[0028] The illumination device 24 is fixed, for example, to the outer periphery of the objective lens 231 so as to surround it, but it does not necessarily have to be fixed directly to the objective lens 231. The illumination device 24 may be fixed, for example, to a revolving nosepiece or other configuration.
[0029] The state of the illumination device 24 (hereinafter referred to as the illumination state), defined by which illumination unit is irradiating the sample S with illumination light, is controlled by the control device 30. The control device 30 can control the emission of light from the light-emitting element 240 on a unit basis of at least one illumination unit, and may sequentially switch between multiple illumination states in which the illumination unit currently illuminates by controlling multiple illumination units to illuminate one by one. For example, the control device 30 may sequentially switch between multiple illumination states in which the illumination unit currently illuminates by controlling multiple illumination units to illuminate one by one in the order of illumination unit 241, illumination unit 242, illumination unit 243, etc. The control device 30 may also control two or more illumination units to illuminate simultaneously, or it may control all illumination units to illuminate simultaneously.
[0030] Figure 4 illustrates the shape of sample S. The advantages of switching between multiple illumination states will be explained with reference to Figure 4. Here, we will explain using the example where the illumination state in which only illumination unit 241 is lit is the first illumination state, the illumination state in which only illumination unit 242 is lit is the second illumination state, and the illumination state in which only illumination unit 243 is lit is the third illumination state.
[0031] In the first illumination state, illumination light L1 with a large incidence angle θ1 irradiates the sample S, allowing even fine irregularities on the surface of the sample S to be visualized with good contrast. On the other hand, illumination light with a large incidence angle does not easily reach the bottom surfaces of grooves such as surfaces R2 and R5. Therefore, it is difficult to observe the entire sample S well using only the image acquired in the first illumination state. Accordingly, it is desirable to irradiate the sample S with illumination light (illumination lights L2, L3) with an incidence angle smaller than θ1 to supplement the observation of areas that are difficult to observe well with a large incidence angle.
[0032] To effectively visualize the bottom surface of a groove, including its fine irregularities, it is desirable to irradiate the sample S with illumination light at the largest possible angle of incidence within the range where the illumination light can reach the bottom surface of the groove. The angle of incidence of the illumination light reaching the bottom surface of the groove decreases as the groove becomes deeper and narrower. For this reason, the second illumination state, in which illumination light L2 with a moderate angle of incidence θ2 (<angle of incidence θ1) is irradiated onto the sample S, is effective for observing the bottom surface R5 of a relatively wide and shallow groove. In contrast, the third illumination state, in which illumination light L3 with the smallest angle of incidence θ3 (<angle of incidence θ2) is irradiated onto the sample S, is effective for observing the bottom surface R2 of a relatively narrow and deep groove.
[0033] Thus, the optimal illumination state differs depending on the region within the sample S. Therefore, in order to image each region within the sample S under the optimal illumination state, it is desirable to use an illumination device 24 capable of realizing multiple illumination states and to sequentially switch between multiple illumination states to image the sample S.
[0034] Furthermore, even in the illumination state where all illumination units are turned on simultaneously (hereinafter referred to as the "full illumination state"), the entire sample S can be illuminated with illumination light. However, the full illumination state is not necessarily superior to illumination states where only some of the illumination units are turned on (for example, the first illumination state, the second illumination state, and the third illumination state). Rather, in many cases, an illumination state in which only illumination light with the optimal incident angle is irradiated is preferable.
[0035] For example, if the sample S is made of a material with high reflectivity, such as a metal, full illumination is likely to cause halation, limiting the area of the sample that can be observed. Furthermore, if the light intensity is adjusted to suppress halation, relatively dark areas become even darker, making it difficult to observe the entire sample clearly. Additionally, if illumination at other angles is simultaneously shone on a region in addition to illumination at the optimal angle, the contrast of the image in that region decreases.
[0036] Therefore, in order to observe the entirety of various samples S well, it is preferable to image the sample while switching between multiple illumination conditions and then combine the resulting multiple images, rather than imaging the sample under full illumination conditions.
[0037] Figure 5 is a flowchart showing an example of the processing performed by the observation device 10. Figure 6 is a diagram illustrating the composite image. Below, a method for generating a composite image that allows for good observation of the entire sample S will be described with reference to Figures 5 and 6.
[0038] First, the observation device 10 switches the illumination state (step S1). Here, the control device 30 changes one or more of the illumination units of the illumination device 24 to the illuminated state, so that the microscope 20 illuminates the sample S in a specific illumination state (for example, the first illumination state).
[0039] Next, the observation device 10 images the sample S (step S2). Here, the control device 30 controls the digital camera 27, which then images the sample S. This generates an image of the sample (imported image) taken under specific lighting conditions.
[0040] Subsequently, the observation device 10 determines whether or not it has switched to all the planned lighting states (step S3). If it determines that it has not switched to all the planned lighting states (step S3NO), it repeats steps S1 to S3 until it determines that it has switched to all the planned lighting states (step S3YES).
[0041] As a result, the sample S is imaged under all planned illumination conditions (for example, the first illumination condition, the second illumination condition, and the third illumination condition), and multiple imaged images (image 81, image 82, and image 83) are generated, as shown in Figure 6. That is, the control device 30 sequentially switches the illumination units that are lit among the multiple illumination units to multiple illumination conditions in which they differ, and acquires multiple images of the sample captured by the digital camera 27.
[0042] Figure 6 shows image 81, which is an image of sample S taken under the first illumination condition; image 82, which is an image of sample S taken under the second illumination condition; and image 83, which is an image of sample S taken under the third illumination condition.
[0043] If it is determined in step S3 that all illumination states have been switched, the observation device 10 combines multiple captured images (step S4). Here, as shown in Figure 6, the control device 30 combines multiple captured images (captured image 81, captured image 82, captured image 83) to generate a new image of the sample, which is a composite image 80. The control device 30 may further display the composite image 80 on the display device 40.
[0044] The method of image synthesis is not particularly limited, but for example, for each region of sample S, an image in which the region is best visualized may be selected from multiple images, and the portion corresponding to that region may be extracted from the selected image. A composite image 80 may be generated by stitching together the images of each extracted region.
[0045] As described above, by performing the processing shown in Figure 5, the observation device 10 can obtain images of the sample S captured under optimal illumination conditions for each region, allowing for good observation of the entire sample S. Furthermore, it is possible to observe a wider variety of samples better than with conventional methods.
[0046] Figure 7 is an example diagram illustrating the configuration of the lighting device 28. Figure 8 is an example diagram illustrating the configuration of the lighting device 29. The observation device 10 may be equipped with the lighting device 28 shown in Figure 7, or the lighting device 29 shown in Figure 8, instead of the lighting device 24.
[0047] The lighting device 28 has multiple lighting units (lighting unit 281, lighting unit 282, lighting unit 283) arranged concentrically around the optical axis. Similarly, the lighting device 29 also has multiple lighting units (lighting unit 291, lighting unit 292, lighting unit 293) arranged concentrically around the optical axis.
[0048] In the illumination device 24, an example was shown in which each of the multiple illumination units (illumination unit 241, illumination unit 242, illumination unit 243) includes multiple light-emitting elements 240 arranged in a ring shape around the optical axis of the objective lens 231. However, each of the multiple illumination units does not necessarily have to include multiple light-emitting elements.
[0049] The illumination device 28 differs from the illumination device 24 in that each of its multiple illumination units includes a light-emitting element having a ring shape centered on the optical axis. Similar to the illumination device 24, the illumination device 28 can also irradiate the sample S with illumination light at different angles relative to the optical axis using multiple illumination units, and can simultaneously illuminate the sample S from various directions centered on the optical axis.
[0050] The illumination device 29 differs from the illumination device 24 in that, instead of each of the multiple illumination units containing multiple light-emitting elements, it includes multiple light guides 290 that guide light from the light source 90, and the output ends of the multiple light guides 290 are arranged in a ring shape around the optical axis. Similar to the illumination device 24, the illumination device 29 also makes it possible to irradiate the sample S with illumination light at different angles to the optical axis using multiple illumination units, and also to simultaneously illuminate the sample S from various directions around the optical axis.
[0051] Although Figure 8 shows an example in which each illumination unit includes multiple light guides, if light guides are included instead of light-emitting elements, each illumination unit only needs to include one or more light guides that guide light from the light source 90. Each illumination unit may, for example, include one light guide having an annular emission end centered on the optical axis.
[0052] The following describes in detail how to visualize a three-dimensional sample S having a height greater than the depth of field of the microscope 20 using the observation device 10 described above. [First Embodiment] Figure 9 is a flowchart of the processing performed by the observation device 10 according to the first embodiment. Figure 10 is an example of an application screen. Figure 11 is a diagram for explaining pre-scan. Figure 12 is a diagram for explaining height calculation. Figure 13 is a diagram for explaining image acquisition for composite images. Figure 14 is a diagram for explaining an example of an image synthesis method. Figure 15 is a diagram for explaining another example of an image synthesis method. Figure 16 is a diagram for explaining image acquisition in pitch feed mode. The following explanation will use the case of displaying a fully focused image as an example.
[0053] When the observation device 10 executes a predetermined program, the process shown in Figure 9 begins. First, the observation device 10 acquires an input for the image acquisition mode (step S11). Here, when the user selects either the pre-scan mode or the pitch feed mode image acquisition mode on the setting area 62 of the application screen 60 shown in Figure 10, which is displayed on the display device 40 by the program execution, the observation device 10 detects the image acquisition mode selected by the user based on the input signal from the input device 50.
[0054] Subsequently, when the user presses button 63 to instruct the display of the full-focus image, the observation device 10 determines the image acquisition mode (step S12). If "Pre-scan" is selected in the setting area 62, the observation device 10 determines that the image acquisition mode is pre-scan mode and pre-scans the sample S (step S13).
[0055] In the pre-scan, as shown in Figure 11, the control device 30 controls the optical head 21 to change the distance between the sample S and the observation optical system 23 at regular intervals (pitch), while controlling the illumination device 24 and the digital camera 27 to acquire an image in a fully illuminated state. That is, the control device 30 repeatedly performs the process of changing the distance of the focusing unit at regular intervals (pitch), and then acquires an image in a fully illuminated state where all of the illumination units are lit. In addition to the illumination device 24, the sample S may also be illuminated using a light source 22.
[0056] Next, the observation device 10 calculates the height of the sample S (step S14). Here, the control device 30 calculates the height of each region of the sample S based on the multiple images acquired in the pre-scan in step S13. In the following explanation, we will describe an example where the height is calculated for each pixel, but the region, which is the unit for calculating the height, is not limited to one pixel of the image acquired in step S13. Multiple pixels may be grouped together as one region, and the height may be calculated for each region.
[0057] The method for calculating height is not particularly limited, but the control device 30 may, for example, create an IZ curve for each pixel (region) as shown in Figure 12, and calculate the height of each region of the sample from the peak position of the IZ curve.
[0058] Once the height of each region of the sample is calculated, the observation device 10 moves the focusing unit (step S15). Here, the control device 30 moves the optical head 21, which is the focusing unit, based on the height calculated in step S14. More specifically, the control device 30 causes the optical head 21 to change the distance between the sample S and the observation optical system 23 so that it focuses on one of the multiple heights calculated in step S14. In other words, the control device 30 causes the optical head 21 to change the distance between the sample S and the observation optical system 23 to a distance corresponding to the multiple heights calculated in step S14.
[0059] Once the focusing mechanism has finished moving, the observation device 10 sequentially switches the illumination state to image the sample S (step S16). Here, the control device 30 sequentially switches to the multiple illumination states described above to acquire multiple images. More specifically, the control device 30 controls the illumination device 24 to illuminate the sample S in the first illumination state, and controls the digital camera 27 to image the sample S illuminated in the first illumination state, thereby acquiring an image. Subsequently, the control device 30 controls the illumination device 24 to switch to the second illumination state, and while illuminating the sample S in the second illumination state, controls the digital camera 27 to image the sample S illuminated in the second illumination state, thereby acquiring an image. Furthermore, the control device 30 controls the illumination device 24 to switch to the third illumination state, and while illuminating the sample S in the third illumination state, controls the digital camera 27 to image the sample S illuminated in the third illumination state, thereby acquiring an image. As a result, the control device 30 acquires multiple images corresponding to multiple illumination states while all are focused at the same height.
[0060] Subsequently, the observation device 10 determines whether to terminate image acquisition (step S17). Here, the control device 30 determines whether to terminate image acquisition based on whether or not images have been acquired at all of the multiple heights calculated in step S14.
[0061] If images have not been acquired at all of the multiple heights, the control device 30 determines that it will not terminate image acquisition and repeats the process from step S15 to step S17 until images have been acquired at all of the multiple heights.
[0062] Specifically, the control device 30 repeatedly performs the process of changing the distance to the focusing unit (step S15) and the process of sequentially switching to multiple illumination states and acquiring multiple images after the process of step S15 (step S16). As a result, as shown in Figure 13, the control device 30 acquires multiple image captures corresponding to multiple illumination states for each height of each region of the sample S calculated in step S14.
[0063] Once image acquisition is complete, the observation device 10 synthesizes multiple captured images to generate a composite image, which is a full-focus image (step S18). Here, the control device 30 generates a full-focus image of the sample S based on multiple captured images acquired by repeating the processes of step S15 and step S16.
[0064] The image synthesis method for generating the all-focus image is not particularly limited, but it is sufficient to use the height of each region of the sample calculated in step S14. The control device 30 can determine the pixel value corresponding to each region of the all-focus image based on the pixel value corresponding to that region in multiple images acquired under multiple illumination conditions while focusing on the height of that region. In other words, the control device 30 can determine the pixel value of the all-focus image corresponding to a region of a certain height based on the pixel value of that region in the captured image acquired under a first illumination condition, an captured image acquired under a second illumination condition, and an captured image acquired under a third illumination condition while focusing on the height of that region. Specifically, the control device 30 may determine the pixel value corresponding to each region of the all-focus image to be the maximum value of the pixel value corresponding to that region in multiple images acquired under multiple illumination conditions while focusing on the height of that region.
[0065] Therefore, as shown in Figure 14, the control device 30 may independently select an image to be used for each region at a certain height from among multiple images acquired while in focus at that height, or one or more images acquired at the same height may be used to generate the all-in-focus image. This makes it possible to use the pixel values of the optimal image for each region, according to the optimal illumination conditions that differ for each region, as the pixel values of the all-in-focus image.
[0066] Furthermore, as shown in Figure 15, the control device 30 may select one image from among multiple images acquired while in focus at a certain height, or multiple images selected one for each height may be used to generate the all-in-focus image. This makes it possible to use the pixel values of images acquired under optimal illumination conditions for each height as the pixel values of the all-in-focus image.
[0067] Furthermore, the selection of the image acquired under the optimal lighting conditions for each height may be determined based on contrast. For example, the image with the highest contrast among multiple images acquired while in focus at that height may be selected as the image acquired under the optimal lighting conditions for that height.
[0068] On the other hand, if "pitch advance" is selected in setting area 62, the observation device 10 determines in step S12 that the image acquisition mode is pitch advance mode, and repeats the process of moving the focus unit (step S19) and the process of sequentially switching the illumination state after step S19 to image the sample S (step S20), as shown in Figure 16.
[0069] Here, the process in step S19 differs from the process in step S15 in that the focusing unit is moved at a predetermined pitch, but the process in step S20 is the same as the process in step S16. That is, in step S19, the control device 30 causes the focusing unit to change the distance between the sample S and the observation optical system 23 at a constant interval (for example, 500 μm), and in step S20, it sequentially switches to the above-mentioned multiple illumination states to acquire multiple images.
[0070] The determination of whether to terminate image acquisition in step S21 can be made, for example, by determining whether the focusing unit has moved outside the specified height range, or whether the specified number of movements have been completed.
[0071] Once image acquisition is complete, the observation device 10 combines multiple captured images to generate a composite image, which is a full-focus image (step S22). Here, the control device 30 generates a full-focus image of the sample S based on multiple images acquired by repeating the processes of step S19 and step S20.
[0072] The image synthesis method for generating a fully focused image is not particularly limited. The control device 30 can determine the pixel value corresponding to each region of the fully focused image based on the pixel values corresponding to that region of multiple images obtained by repeating the processing in step S19 and the processing in step S20. Specifically, the control device 30 may determine the pixel value corresponding to each region of the fully focused image to be the maximum value of the pixel values corresponding to that region of multiple images obtained repeatedly.
[0073] In addition, in pitch feed mode, the height of a region may be calculated based on the image having the maximum value for each region identified in step S22.
[0074] When a full-focus image is generated in step S18 or step S22, the observation device 10 outputs the generated full-focus image (step S23). Here, the control device 30 displays the full-focus image on the display device 40. Specifically, the control device 30 displays the full-focus image, for example, in the image display area 61 of the application screen 60. This allows the user to observe the entire sample S well by observing the full-focus image.
[0075] As described above, the observation device 10 allows for good visualization of a three-dimensional sample S by performing the processing shown in Figure 9. Therefore, various samples can be observed well. Furthermore, by selecting the pre-scan mode in the observation device 10, multiple images corresponding to multiple illumination conditions are acquired at the height of each precisely identified region. This allows for accurate identification of the three-dimensional shape of the sample S, and a full-focus image can be generated using images acquired with each region in precise focus. Moreover, by selecting the pitch-feed mode, multiple images corresponding to multiple illumination conditions can be acquired by changing the height at regular intervals without calculating the height in advance, and a full-focus image can be generated from these images. This allows for the generation of a full-focus image in a shorter time than when the pre-scan mode is selected. Thus, the observation device 10 allows users to choose whether to prioritize accuracy or speed when creating a full-focus image by selecting the image acquisition mode, thus addressing various situations the user may be in.
[0076] In addition, although the above example shows the display of a full-focus image, the user may press button 64 to instruct the display of a three-dimensional image, and a three-dimensional image may be generated as a composite image instead of a full-focus image. That is, the control device 30 may generate a new image of the sample, which may be a full-focus image or a three-dimensional image, based on multiple images repeatedly acquired in response to the user's operation.
[0077] [Second Embodiment] Figure 17 is a flowchart of the processing performed by the observation device 10 according to the second embodiment. Figure 18 is another example of the application screen. Hereinafter, the explanation will be given using the case where the full-focus image is displayed as an example, similar to the first embodiment.
[0078] This embodiment differs from the first embodiment in that, in addition to the image acquisition mode, the user can select an image synthesis mode, and a fully focused image is generated according to the selected image synthesis mode. Other aspects are the same as the first embodiment.
[0079] When the observation device 10 executes a predetermined program and the process shown in Figure 17 begins, the observation device 10 first acquires input for the image acquisition mode and the image synthesis mode (step S31). Here, when the user selects either the pre-scan mode or the pitch feed mode image acquisition mode on the setting area 62 of the application screen 60a shown in Figure 18, which is displayed on the display device 40 by program execution, the observation device 10 detects the image acquisition mode selected by the user based on the input signal from the input device 50. Also, when the user selects either the high-brightness mode or the low-reflectance mode image synthesis mode on the setting area 66 of the application screen 60a, the observation device 10 detects the image synthesis mode selected by the user based on the input signal from the input device 50.
[0080] Subsequently, when the user presses button 63 to instruct the display of the full-focus image, the observation device 10 determines the image acquisition mode (step S32). If "Pre-scan" is selected in the setting area 62, the observation device 10 determines that the image acquisition mode is pre-scan mode, pre-scans the sample S (step 33), and then calculates the height of the sample S (step S34).
[0081] Once the height of each region of the sample is calculated, the observation device 10 repeats the process of moving the focus unit to a position corresponding to the calculated height (step S35) and sequentially switching the illumination state to image the sample S (step S36) until it has moved to a position corresponding to all the calculated heights (step S37YES). Note that the process from step S33 to step S37 is the same as the process from step S13 to step S17 in Figure 9.
[0082] Once image acquisition is complete, the observation device 10 combines multiple captured images to generate a composite image, which is a full-focus image (step S38). Here, the control device 30 generates a full-focus image of the sample S based on multiple captured images acquired by repeating the processes of step S35 and step S36.
[0083] More specifically, as shown in Figure 18, when "high brightness" is selected in the setting area 66, the control device 30 determines the pixel value corresponding to each area of the full-focus image to be the maximum value of the pixel value corresponding to that area in multiple images acquired under multiple lighting conditions while focusing on the height of that area. Furthermore, if a threshold for pixel value (brightness) is set in advance in the setting area 66, the control device 30 may determine the pixel value within that threshold. In other words, the pixel value corresponding to each area of the full-focus image may be determined to be the highest pixel value below the threshold among the pixel values corresponding to that area in multiple images acquired under multiple lighting conditions while focusing on the height of that area. On the other hand, when "low reflectivity" is set in the setting area 66, the control device 30 determines the pixel value corresponding to each area of the full-focus image to be the minimum value of the pixel value corresponding to that area in multiple images acquired under multiple lighting conditions while focusing on the height of that area. Furthermore, if a threshold for pixel value (brightness) is set in advance in the setting area 66, the control device 30 may determine the pixel value at or above that threshold. In other words, the pixel value corresponding to each region of the fully focused image may be determined as the lowest pixel value above a threshold among the pixel values corresponding to that region in multiple images acquired under multiple lighting conditions while focusing on the height of that region.
[0084] On the other hand, if "pitch advance" is selected in setting area 62, the observation device 10 determines in step S32 that the image acquisition mode is pitch advance mode, and repeats the process of moving the focusing unit at a constant pitch (step S39) and the process of sequentially switching the illumination state after step S39 to image the sample S (step S40) until, for example, the focusing unit moves outside the specified height range (step S41 YES). Note that the process from step S39 to step S41 is the same as the process from step S19 to step S22 in Figure 9.
[0085] Once image acquisition is complete, the observation device 10 combines multiple captured images to generate a composite image, which is a full-focus image (step S42). Here, the control device 30 generates a full-focus image of the sample S based on multiple images acquired by repeating the processes of step S39 and step S40.
[0086] More specifically, if a threshold for pixel value (luminance) is set in advance in the setting area 66, the control device 30 may determine the pixel value within that threshold. In other words, the pixel value corresponding to each area of the fully focused image may be determined to be the highest pixel value among the pixel values corresponding to that area of multiple images acquired repeatedly, that is below the threshold.
[0087] When a full-focus image is generated in step S38 or step S42, the observation device 10 outputs the generated full-focus image (step S43). This process is the same as step S23 in Figure 9.
[0088] As described above, even when the observation device 10 performs the process shown in Figure 17 instead of the process shown in Figure 9, it is possible to visualize the three-dimensional sample S well, and obtain the same effects as in the first embodiment. In addition, in this embodiment, the user can select the image synthesis mode. Specifically, by selecting the high brightness mode, it is possible to generate a full-focus image prioritizing brightness, and by selecting the low reflectivity mode, it is possible to generate a full-focus image prioritizing the suppression of halation. Therefore, by selecting the optimal image synthesis mode based on the material of the sample, etc., the user can obtain a bright image while suppressing halation.
[0089] [Third Embodiment] Figure 19 is a flowchart of the processing performed by the observation device 10 according to the third embodiment. Hereinafter, the explanation will be given using the case where the full-focus image is displayed, similar to the first embodiment.
[0090] This embodiment differs from the first embodiment in that multiple images acquired under multiple lighting conditions are displayed in a list, and an image selected from the displayed list is used for image synthesis. Other aspects are the same as the first embodiment.
[0091] When the observation device 10 executes a predetermined program and starts the process shown in Figure 19, it first obtains an input for the image acquisition mode (step S51). If the user then selects the pre-scan mode, the processes from steps S53 to S56 are performed. These processes are the same as the processes from steps S13 to S16 in Figure 9.
[0092] Subsequently, the observation device 10 displays a list of the multiple images acquired in step S56 (step S57). Here, the control device 30 displays the multiple images acquired under multiple lighting conditions at the current height reached in step S55 (for example, an image of the first lighting condition, an image of the second lighting condition, and an image of the third lighting condition) in a comparable arrangement in the image display area 61 of the application screen. Furthermore, when the user selects one image from the displayed list (step S58 YES), the control device 30 stores the selected image as the representative image for the current height.
[0093] The observation device 10 repeats the process from step S55 to step S58 until it moves to a position corresponding to all the heights calculated in step S54 (step S59 YES). Once image acquisition is complete, the observation device 10 synthesizes multiple captured images to generate a composite image, which is a full-focus image (step S60). In this process, the full-focus image is generated by extracting and stitching together the portion corresponding to the region of each height from the representative image of each height.
[0094] On the other hand, if the user selects the pitch feed mode, steps S61 and S62 are performed. These processes are the same as steps S19 and S20 in Figure 9.
[0095] Subsequently, the observation device 10 displays a list of the multiple images acquired in step S62 (step S63). Here, the control device 30 displays the multiple images acquired under multiple lighting conditions at the current height reached in step S61 (for example, an image of the first lighting condition, an image of the second lighting condition, and an image of the third lighting condition) in a comparable arrangement in the image display area 61 of the application screen. Furthermore, when the user selects one image from the list of images (step S64 YES), the control device 30 stores the selected image as the representative image for the current height.
[0096] The observation device 10 repeats the process from step S61 to step S64 until, for example, the focusing unit moves outside the specified height range (step S65YES). Once image acquisition is complete, the observation device 10 combines multiple captured images to generate a composite image, which is a full-focus image (step S66). This process is the same as the process in step S22 of Figure 9.
[0097] When a full-focus image is generated in step S60 or step S66, the observation device 10 outputs the generated full-focus image (step S67). This process is the same as step S23 in Figure 9.
[0098] As described above, even when the observation device 10 performs the process shown in Figure 19 instead of the process shown in Figure 9, it is possible to visualize the three-dimensional sample S well, and obtain the same effects as in the first embodiment. Furthermore, in this embodiment, the user can select an image with the optimal illumination state for each height. Therefore, it is possible to obtain a fully focused image that reflects the user's preference.
[0099] [Fourth Embodiment] Figure 20 is a flowchart of the processing performed by the observation device 10 according to the fourth embodiment. Figure 21 is yet another example of the application screen. Below, we will explain the process of reproducing the state of the microscope 20 when the selected image was acquired by selecting an image from the list display.
[0100] After the observation device 10 executes a predetermined program and generates a fully focused image by the process shown in Figure 9, for example, when the user presses button 65 to instruct the display of a list (step S71YES), the observation device 10 displays the captured images in a list (step S72). Here, the control device 30 displays a list of multiple images acquired to generate a fully focused image. More specifically, the control device 30 displays a list of multiple images acquired by repeatedly performing the process of changing the distance between the sample S and the observation optical system 23 in the focusing unit, and then sequentially switching to multiple illumination states after changing the distance to acquire multiple images, on the display device 40.
[0101] The multiple images displayed in the list may, for example, be arranged in a sequence, as shown in the application screen 70 in Figure 21, with multiple images acquired under different lighting conditions for each height (z position). By viewing the displayed images, the user can see how the appearance of the sample S changes depending on the height and lighting conditions.
[0102] Subsequently, when the observation device 10 detects that the user has selected one image from the list of displayed images (step S73YES), the focusing unit moves to a position corresponding to the selected image (hereinafter referred to as the selected image) (step S74) and switches to an illumination state corresponding to the selected image (step S75). In steps S74 and S75, the control device 30 controls the focusing unit to change the distance between the sample S and the observation optical system 23 to a distance corresponding to the selected image, and controls at least some of the multiple illumination units to switch to an illumination state corresponding to the selected image. This reproduces the state of the microscope 20 when the image selected by the user was acquired.
[0103] As described above, by performing the process shown in Figure 20, the observation device 10 can easily reproduce the state of the microscope 20 when any image in the list of displayed images was acquired.
[0104] In Figure 20, an example is shown in which one image is selected from a list of displayed images, and the state of the microscope 20 at the time the selected image was acquired is reproduced. However, images may also be selected from the list of displayed images at different heights. The control device 30 may generate a full-focus image or a three-dimensional image based on the image selected by the user at each height, that is, at each distance between the sample S and the observation optical system 23.
[0105] Figure 22 is a diagram illustrating the hardware configuration of a computer 100 for realizing the control device 30 according to the embodiment described above. As shown in Figure 20, the computer 100 includes a processor 101, memory 102, storage device 103, reader 104, communication interface 106, and input / output interface 107 as its hardware configuration. The processor 101, memory 102, storage device 103, reader 104, communication interface 106, and input / output interface 107 are connected to each other, for example, via a bus 108.
[0106] The processor 101 may be a single processor, a multi-processor, or a multi-core processor. The processor 101 operates as the control unit of the observation device 10 by reading and executing the program stored in the storage device 103.
[0107] Memory 102 is, for example, a semiconductor memory and may include a RAM area and a ROM area. Storage device 103 is, for example, a hard disk, a semiconductor memory such as flash memory, or an external storage device.
[0108] The reader 104 accesses the removable storage medium 105, for example, according to instructions from the processor 101. The removable storage medium 105 can be implemented by, for example, a semiconductor device, a medium through which information is input / output by magnetic action, or a medium through which information is input / output by optical action. A semiconductor device is, for example, a USB (Universal Serial Bus) memory. A medium through which information is input / output by magnetic action is, for example, a magnetic disk. A medium through which information is input / output by optical action is, for example, a CD (Compact Disc)-ROM, a DVD (Digital Versatile Disk), a Blu-ray Disc, etc. (Blu-ray is a registered trademark).
[0109] The communication interface 106 communicates with other devices, for example, according to instructions from the processor 101. The input / output interface 107 is, for example, an interface between an input device and an output device. The input device is, for example, a device such as a keyboard, mouse, or touch panel that receives instructions from the user. The output device is, for example, a display device such as a display, and an audio device such as a speaker.
[0110] The program executed by the processor 101 is provided to the computer 100 in the following form, for example. (1) It is pre-installed on the storage device 103. (2) Provided by a removable storage medium 105. (3) Provided from a server such as a program server.
[0111] The hardware configuration of the computer 100 for realizing the control device 30 described with reference to Figure 22 is illustrative, and the embodiment is not limited thereto. For example, some of the above configuration may be deleted, or new configurations may be added. In another embodiment, for example, some or all of the functions of the calculation unit 42 described above may be implemented as hardware such as an FPGA (Field Programmable Gate Array), SoC (System-on-a-Chip), ASIC (Application Specific Integrated Circuit), and PLD (Programmable Logic Device). That is, any electrical circuit included in the control device 30 may perform the internal prediction processing described above.
[0112] The embodiments described above are specific examples provided to facilitate understanding of the invention, and the present invention is not limited to these embodiments. Modified forms of the embodiments described above and alternative forms that replace the embodiments described above may be included. In other words, each embodiment can be modified in terms of its components without departing from its spirit and scope. Furthermore, new embodiments can be implemented by appropriately combining multiple components disclosed in one or more embodiments. In addition, some components may be deleted from the components shown in each embodiment, or some components may be added to the components shown in an embodiment. Moreover, the processing steps shown in each embodiment may be performed in a different order, as long as they do not contradict each other. That is, the observation device of the present invention can be modified in various ways without departing from the scope of the claims.
[0113] In the embodiment described above, an example was shown in which the control device 30 controls the light emission of light-emitting elements on a lighting unit basis. However, the control device 30 may also control the light emission of light-emitting elements on an individual light-emitting element basis. Furthermore, the control device 30 may allow only some of the light-emitting elements in the lighting unit to emit light, while keeping the remaining elements do not. Such light emission control may be performed for the purpose of adjusting the light intensity. In addition, the control device 30 may divide the light-emitting elements within the lighting unit into multiple groups and allow each group to emit light. For example, multiple light-emitting elements arranged in the circumferential direction may be divided into four circumferential sections, creating four groups, and the light-emitting elements belonging to each of the four groups may be allowed to emit light sequentially for each group. Such light emission control may be performed for the purpose of giving directionality to the illumination.
[0114] In the embodiment described above, an example was shown in which the lighting device has three lighting units, but the number of lighting units is not limited to three. The lighting device may have two or more lighting units.
[0115] In the embodiment described above, an example was shown in which all images are displayed in a list. However, the control device 30 may select the brightest or darkest image for each height and display one selected image for each height in a list.
[0116] In the embodiment described above, an example was shown in which multiple illumination units are fixed at the same height. However, it is sufficient for multiple illumination units to illuminate the sample at different angles, and they do not necessarily need to be fixed at the same height. Nevertheless, fixing multiple illumination units at the same height can reduce the difference in light intensity that occurs when switching between illumination units that are lit.
[0117] In the embodiment described above, an example was shown in which a fixed-width pitch is used in pitch feed mode, but it is not always necessary to move the focusing unit in a fixed-width manner in pitch feed mode. In the pitch feed mode described above, a fixed-width pitch was used because the height of the sample S was unknown, but if a full-focus image or a three-dimensional image has been previously generated for a similar sample, the height of the sample may be estimated using the height information acquired at that time, and the focusing unit may be moved to a position corresponding to the estimated height.
[0118] In the embodiment described above, an example was shown in which each of the multiple illumination units has an annular shape and includes multiple light-emitting elements arranged in an annular pattern. However, the shape of the illumination unit is not limited to an annular shape, nor is the arrangement of the multiple light-emitting elements limited to an annular pattern. The shape of the illumination unit only needs to be an annular shape, and the arrangement of the multiple light-emitting elements only needs to be annular. Therefore, for example, the shape of the illumination unit may be a rectangular annular shape, and the multiple light-emitting elements may be arranged in a rectangular annular pattern. [Explanation of symbols]
[0119] 10 Observation device 20 Microscopes 21 Optical Heads 22, 90 light source 23 Observation Optical System 231 Objective lens 24, 28, 29 Lighting equipment 240 light-emitting elements 241-243, 281-283, 291-293 Lighting section 25 stages 25a XY Stage 25b Z Stage 26 frames 27 Digital Cameras 271 Image Sensor 290 Light guide 30 Control device 40 Display device 50 Input devices 60, 60a, 70 Application Screens 61 Image display area 62, 66 Setting Area Buttons 63-65 80 Composite Images 81-83 Acquired images 100 Computers 101 Processors 102 memory 103 Storage device 104 Reading device 105 Storage medium 106 Communication Interface 107 Input / Output Interfaces 108 Bus L1~L3 illumination light R1~R5 side S sample
Claims
1. An imaging unit for imaging the sample, An observation optical system that projects an optical image of the sample onto the imaging unit, A plurality of illumination units that irradiate the sample with illumination light at different angles relative to the optical axis of the observation optical system, each having a different angle of incidence to the sample, wherein the illumination units are arranged concentrically around the optical axis and at the same height, and by switching between the illuminated illumination units, the system can sequentially switch between a first illumination state in which the sample is irradiated at a first angle of incidence and a second illumination state in which the sample is irradiated at a second angle of incidence. A control unit that acquires a plurality of images of the sample captured by the imaging unit by sequentially switching the illuminated illumination unit among the plurality of illumination units to a plurality of different illumination states, comprising: a control unit that acquires the plurality of images by obtaining at least an image of the sample captured in a first illumination state and an image of the sample captured in a second illumination state. The control unit generates a new image of the sample based on the multiple images obtained by sequentially switching between the multiple illumination states. An observation device characterized by the following features.
2. In the observation apparatus described in claim 1, further, The system includes a focusing unit that changes the distance between the sample and the observation optical system, The control unit repeats a first process of causing the focusing unit to change the distance, and a second process of sequentially switching to the multiple illumination states after the first process to acquire the multiple images. An observation device characterized by the following features.
3. In the observation apparatus described in claim 2, The control unit generates a new image of the sample, which is either a full-focus image or a three-dimensional image, based on the plurality of images obtained by repeating the first and second processes. An observation device characterized by the following features.
4. In the observation apparatus described in claim 3, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image, based on the pixel values corresponding to that region in the plurality of images obtained by repeating the first and second processes. An observation device characterized by the following features.
5. In the observation apparatus according to claim 3 or claim 4, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image to be the maximum value of the pixel values corresponding to that region in the plurality of images obtained by repeating the first process and the second process. An observation device characterized by the following features.
6. In the observation apparatus according to claim 3 or claim 4, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image to be the highest value among the pixel values corresponding to that region in the plurality of images obtained by repeating the first and second processes, which is below a threshold. An observation device characterized by the following features.
7. In the observation apparatus according to claim 3 or claim 4, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image from among the pixel values corresponding to that region in a plurality of images obtained by repeating the first and second processes, according to the user's selection. An observation device characterized by the following features.
8. In the observation apparatus described in claim 3, The control unit, The height of each region of the aforementioned sample is calculated, For each region of the sample, the pixel value corresponding to that region in the new image is determined based on the pixel values corresponding to that region in the plurality of images acquired under the plurality of illumination conditions while focusing on the calculated height of that region. An observation device characterized by the following features.
9. In the observation apparatus described in claim 8, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image to be the maximum value of the pixel value corresponding to that region in the plurality of images acquired under the plurality of illumination conditions while focusing on the calculated height of that region. An observation device characterized by the following features.
10. In the observation apparatus described in claim 8, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image to be the highest value among the pixel values corresponding to that region in the plurality of images acquired under the plurality of illumination conditions, while focusing on the calculated height of that region, and which is below a threshold value. An observation device characterized by the following features.
11. In the observation apparatus described in claim 8, The control unit determines, for each region of the sample, the pixel value corresponding to that region in the new image from among the pixel values corresponding to that region in the plurality of images acquired under the plurality of illumination conditions while focusing on the calculated height of that region, according to the user's selection. An observation device characterized by the following features.
12. In the observation apparatus described in claim 2, The control unit displays the plurality of images obtained by repeating the first process and the second process in a list on the display unit. An observation device characterized by the following features.
13. In the observation apparatus according to claim 12, The control unit, in response to the user's selection of one image from the multiple images displayed in the display unit, controls the focusing unit to change the distance between the sample and the observation optical system to the distance corresponding to the selected image, and controls at least some of the multiple illumination units to switch to the illumination state corresponding to the selected image. An observation device characterized by the following features.
14. In the observation apparatus according to claim 12, The control unit generates a new image of the sample, which is either a full-focus image or a three-dimensional image, based on the image selected by the user from among the multiple images displayed in a list on the display unit, for each distance between the sample and the observation optical system. An observation device characterized by the following features.
15. In the observation apparatus described in claim 2, The control unit, The process involves repeatedly performing a third process in which the focusing unit changes the distance at regular intervals, and a fourth process in which, after the third process, an image is acquired in a fully illuminated state where all of the multiple illumination units are lit. Based on the multiple images obtained by repeating the first and second processes, the height of each region of the sample is calculated. In the first process described above, the focusing unit is made to change the distance to a distance corresponding to the height calculated above. An observation device characterized by the following features.
16. In the observation apparatus described in claim 2, The control unit causes the focusing unit to change the distance at regular intervals during the first process. An observation device characterized by the following features.
17. In the observation apparatus according to any one of claims 1 to 16, Each of the aforementioned multiple illumination units includes a plurality of light-emitting elements arranged in a ring shape around the optical axis, or a light-emitting element having a ring shape around the optical axis. An observation device characterized by the following features.
18. In the observation apparatus according to any one of claims 1 to 16, Each of the aforementioned multiple illumination units includes a plurality of light guides that guide incident light, the output ends of which are arranged in a ring around the optical axis, or a light guide that guides incident light and has an annular output end around the optical axis. An observation device characterized by the following features.
19. In the observation apparatus according to any one of claims 1 to 18, The plurality of illumination units are arranged at positions at different distances from the optical axis. An observation device characterized by the following features.